Ecological Succession of Wetlands

2022 ◽  
pp. 128-149
Author(s):  
Dwaipayan Sinha ◽  
Soumi Datta ◽  
Vidhi Chaudhary ◽  
Debolina Banerjee ◽  
Rituparna Kundu Chaudhuri
Keyword(s):  
Carbon Dioxide ◽  
Community Structure ◽  
Climatic Changes ◽  
Ecological Succession ◽  
Present Condition ◽  
Over Time

The change in community structure induced by environmental perturbances over time is called ecological succession and results in modification of community structure in a particular ecosystem. However, with climatic changes and pollution, wetlands are most likely to have modified their successional trails, especially as these ecosystems are exposed to various fluctuating water rhythms enhanced carbon dioxide, salinity invasion, and climatic temperatures. The chapter is an attempt to review the present condition of wetlands with respect to pollution and its impact on successional patterns.

An Experimental Study of Nonequilibrium Carbon Dioxide/Oil Interactions

SPE Journal ◽  
2018 ◽  
Vol 23 (05) ◽  
pp. 1768-1783 ◽  
Author(s):  
Mahmood Reza Yassin ◽  
Ali Habibi ◽  
Ashkan Zolfaghari ◽  
Sara Eghbali ◽  
Hassan Dehghanpour
Keyword(s):  
Carbon Dioxide ◽  
Experimental Study ◽  
Natural Convection ◽  
Visual Cell ◽  
Bulk Oil ◽  
High Pressure High Temperature ◽  
Light Oil ◽  
Condensing Flows ◽  
Carbon Dioxide Co2 ◽  
Over Time

Summary In this study, we use a custom-designed visual cell to investigate nonequilibrium carbon dioxide (CO2)/oil interactions under high-pressure/high-temperature conditions. We visualize the CO2/oil interface and measure the visual-cell pressure over time. We perform five sets of visualization tests. The first three tests aim at investigating interactions of gaseous (g), liquid (l), and supercritical (sc) CO2 with a Montney (MTN) oil sample. In the fourth test, to visualize the interactions in the bulk oil phase, we replace the opaque MTN oil with a translucent Duvernay (DUV) light oil (LO). Finally, we conduct an N2(sc)/oil test to compare the results with those of CO2(sc)/oil test. We also compare the results of nonequilibrium CO2/oil interactions with those obtained from conventional pressure/volume/temperature (PVT) tests. Results of the first three tests show that oil immediately expands upon injection of CO2 into the visual cell. CO2(sc) leads to the maximum oil expansion followed by CO2(l) and CO2(g). Furthermore, the rate of oil expansion in the CO2(sc)/oil test is higher than that in CO2(l)/oil and CO2(g)/oil tests. We also observe extracting and condensing flows at the CO2(l)/oil and CO2(sc)/oil interfaces. Moreover, we observe density-driven fingers inside the LO phase because of the local increase in the density of LO. The results of PVT tests show that the density of the CO2/oil mixture is higher than that of the CO2-free oil, explaining the density-driven natural convection during CO2(sc) injection into the visual cell. We do not observe either extracting/condensing flows or density-driven mixing for the N2(sc)/oil test, explaining the low expansion of oil in this test. The results suggest that the combination of density-driven natural convection and extracting/condensing flows enhances CO2(sc) dissolution into the oil phase, leading to fast oil expansion after CO2(sc) injection into the visual cell.

scholarly journals Ecological Succession of Bacterial Communities during Conventionalization of Germ-Free Mice

2012 ◽  
Vol 78 (7) ◽  
pp. 2359-2366 ◽  
Author(s):  
Merritt G. Gillilland ◽  
John R. Erb-Downward ◽  
Christine M. Bassis ◽  
Michael C. Shen ◽  
Galen B. Toews ◽  
...  
Keyword(s):  
Bacterial Community ◽  
16S Rrna ◽  
Bacterial Communities ◽  
Structural Heterogeneity ◽  
Ecological Succession ◽  
Rrna Gene ◽  
Gi Tract ◽  
Content Type ◽  
Germ Free ◽  
Over Time

ABSTRACTLittle is known about the dynamics of early ecological succession during experimental conventionalization of the gastrointestinal (GI) tract; thus, we measured changes in bacterial communities over time, at two different mucosal sites (cecum and jejunum), with germfree C57BL/6 mice as the recipients of cecal contents (input community) from a C57BL/6 donor mouse. Bacterial communities were monitored using pyrosequencing of 16S rRNA gene amplicon libraries from the cecum and jejunum and analyzed by a variety of ecological metrics. Bacterial communities, at day 1 postconventionalization, in the cecum and jejunum had lower diversity and were distinct from the input community (dominated by eitherEscherichiaorBacteroides). However, by days 7 and 21, the recipient communities had become significantly diverse and the cecal communities resembled those of the donor and donor littermates, confirming that transfer of cecal contents results in reassembly of the community in the cecum 7 to 21 days later. However, bacterial communities in the recipient jejunum displayed significant structural heterogeneity compared to each other or the donor inoculum or the donor littermates, suggesting that the bacterial community of the jejunum is more dynamic during the first 21 days of conventionalization. This report demonstrates that (i) mature input communities do not simply reassemble at mucosal sites during conventionalization (they first transform into a “pioneering” community and over time take on the appearance, in membership and structure, of the original input community) and (ii) the specific mucosal environment plays a role in shaping the community.

scholarly journals Faecal Microbiota Dynamics and their Relation to Disease Course in Crohn’s Disease

2019 ◽  
Vol 13 (10) ◽  
pp. 1273-1282 ◽  
Author(s):  
Gianluca Galazzo ◽  
Danyta I Tedjo ◽  
Dion S J Wintjens ◽  
Paul H M Savelkoul ◽  
Ad A M Masclee ◽  
...  
Keyword(s):  
Crohn’S Disease ◽  
Community Structure ◽  
Microbial Community ◽  
Disease Activity ◽  
Microbial Community Structure ◽  
Disease Course ◽  
Microbiota Composition ◽  
Faecal Microbiota ◽  
Over Time

Abstract Background Microbial shifts have been associated with disease activity in Crohn’s disease [CD], but findings on specific taxa are inconsistent. This may be due to differences in applied methods and cross-sectional study designs. We prospectively examined the faecal microbiota in adult CD patients with changing or stable disease course over time. Methods Faeces were collected at two time-points from 15 healthy control individuals [HCs], 35 CD patients who were in remission and who maintained remission [RRs], and 22 CD patients during remission and also during subsequent exacerbation [RAs]. The microbial composition was assessed by 16S rRNA [V4] gene sequencing. Results Compared with HCs, patients with CD had a lower microbial richness [p = 0.0002] and diversity [p = 0.005]. Moreover, the microbial community structure of a subset of patients, clustered apart from HCs, was characterized by low microbial diversity and Faecalibacterium abundance. Patients within this cluster did not differ with respect to long-term disease course compared with patients with a ‘healthy-appearing’ microbiota. Over time, microbial richness and diversity did not change in RR versus RA patients. Although the microbial community structure of both RR and RA patients was less stable over time compared with that of HCs, no differences were observed between the patient groups [p = 0.17]; nor was the stability impacted by Montreal classification, medication use, or surgery. Conclusion The altered microbiota composition and stability in CD was neither associated with disease activity nor long-term disease course, questioning its involvement in the development of an exacerbation. The aberrant microbiota composition in a subset of CD patients warrants further exploration of a more microbiota-driven etiology in this group.

Plasma Decomposition of Carbon Dioxide: Simulations and Experiments

2019 ◽  
Author(s):  
Kamau Wright ◽  
Robert Galvez
Keyword(s):  
Carbon Dioxide ◽  
Co2 Concentration ◽  
Plasma Discharges ◽  
Electrical Parameters ◽  
Plasma System ◽  
Process Gas ◽  
Plasma Decomposition ◽  
Carbon Dioxide Co2 ◽  
Co2 Decomposition ◽  
Over Time

Abstract Simulations and experiments are conducted to model, simulate, test and demonstrate the effect of plasma discharges on decomposition of carbon dioxide (CO2). A pin-to-plane discharge is employed in gas samples containing CO2. A high voltage plasma system is used which was previously shown to be able to decrease CO2 concentration in gas samples. The discharge is modeled and described, including monitoring electrical parameters such as current and voltage. The present study investigated plasma decomposition of carbon dioxide experimentally, and through simulation. A plasma micro-discharge was utilized to better understand plasma-CO2 interactions. Enhancements are suggested to help increase the efficiency and yield of the plasma-CO2 decomposition process. Gas samples are analyzed over time using a CO2 meter.

Sir Nicholas John Shackleton. 23 June 1937 — 24 January 2006

2011 ◽  
Vol 57 ◽  
pp. 435-462 ◽  
Author(s):  
Ian Nicholas McCave ◽  
Henry Elderfield
Keyword(s):  
Carbon Dioxide ◽  
Global Warming ◽  
Climatic Changes ◽  
Future Climate ◽  
The Past ◽  
Earth’S Climate ◽  
Natural Climate ◽  
Precise Role ◽  
Present Understanding

Nick Shackleton was an international scientist of great renown who fundamentally changed our understanding of how Earth processes work. His research on ancient oceans and climates was both innovative and pioneering, and he clarified the precise role of carbon dioxide in warming and cooling the Earth's climate. His work contributed greatly to our present understanding of the mechanism and causes of global warming. When he began his research, the investigation of past climatic changes was an area of ‘academic’ interest only. Four decades later, his lifetime achievements define the emergence of our understanding of the operation of Earth's natural climate system. This understanding of the past is now central to efforts to predict the future climate we have begun to create. As well as his many scientific accomplishments, Nick Shackleton excelled in another area, that of music, which was almost as important to him as science, and he was a very accomplished clarinet player. In his work he was spirited and curiosity-driven. He let his students and an entire community share in his brilliance and vision.

scholarly journals Recent responses to climate change reveal the drivers of species extinction and survival

2020 ◽  
Vol 117 (8) ◽  
pp. 4211-4217 ◽  
Author(s):  
Cristian Román-Palacios ◽  
John J. Wiens
Keyword(s):  
Climate Change ◽  
Animal Species ◽  
Biodiversity Loss ◽  
Climatic Changes ◽  
Important Work ◽  
Species Extinction ◽  
Major Threat ◽  
Niche Shifts ◽  
Local Extinctions ◽  
Over Time

Climate change may be a major threat to biodiversity in the next 100 years. Although there has been important work on mechanisms of decline in some species, it generally remains unclear which changes in climate actually cause extinctions, and how many species will likely be lost. Here, we identify the specific changes in climate that are associated with the widespread local extinctions that have already occurred. We then use this information to predict the extent of future biodiversity loss and to identify which processes may forestall extinction. We used data from surveys of 538 plant and animal species over time, 44% of which have already had local extinctions at one or more sites. We found that locations with local extinctions had larger and faster changes in hottest yearly temperatures than those without. Surprisingly, sites with local extinctions had significantly smaller changes in mean annual temperatures, despite the widespread use of mean annual temperatures as proxies for overall climate change. Based on their past rates of dispersal, we estimate that 57–70% of these 538 species will not disperse quickly enough to avoid extinction. However, we show that niche shifts appear to be far more important for avoiding extinction than dispersal, although most studies focus only on dispersal. Specifically, considering both dispersal and niche shifts, we project that only 16–30% of these 538 species may go extinct by 2070. Overall, our results help identify the specific climatic changes that cause extinction and the processes that may help species to survive.

scholarly journals Randomized Study Comparing the Effect of Carbon Dioxide Insufflation on Veins using 2 Types of Endoscopic and Open Vein Harvesting

2017 ◽  
Vol 12 (5) ◽  
pp. 320-328
Author(s):  
Bhuvaneswari Krishnamoorthy ◽  
William R. Critchley ◽  
Janesh Nair ◽  
Ignacio Malagon ◽  
John Carey ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Insufflation ◽  
Endoscopic Vein Harvesting ◽  
Arterial Carbon Dioxide ◽  
Harvesting Technique ◽  
End Tidal Carbon Dioxide ◽  
End Tidal ◽  
Endothelial Integrity ◽  
Over Time ◽  
Vein Harvesting

Objective The aim of the study was to assess whether the use of carbon dioxide insufflation has any impact on integrity of long saphenous vein comparing 2 types of endoscopic vein harvesting and traditional open vein harvesting. Methods A total of 301 patients were prospectively randomized into 3 groups. Group 1 control arm of open vein harvesting (n = 101), group 2 closed tunnel (carbon dioxide) endoscopic vein harvesting (n = 100) and Group 3 open tunnel (carbon dioxide) endoscopic vein harvesting (open tunnel endoscopic vein harvesting) (n = 100). Each group was assessed to determine the systemic level of partial arterial carbon dioxide, end-tidal carbon dioxide, and pH. Three blood samples were obtained at baseline, 10 minutes after start of endoscopic vein harvesting, and 10 minutes after the vein was retrieved. Vein samples were taken immediately after vein harvesting without further surgical handling to measure the histological level of endothelial damage. A modified validated endothelial scoring system was used to compare the extent of endothelial stretching and detachment. Results The level of end-tidal carbon dioxide was maintained in the open tunnel endoscopic vein harvesting and open vein harvesting groups but increased significantly in the closed tunnel endoscopic vein harvesting group ( P = 0.451, P = 0.385, and P < 0.001). Interestingly, partial arterial carbon dioxide also did not differ over time in the open tunnel endoscopic vein harvesting group ( P = 0.241), whereas partial arterial carbon dioxide reduced significantly over time in the open vein harvesting group ( P = 0.001). A profound increase in partial arterial carbon dioxide was observed in the closed tunnel endoscopic vein harvesting group ( P < 0.001). Consistent with these patterns, only the closed tunnel endoscopic vein harvesting group demonstrated a sudden drop in pH over time ( P < 0.001), whereas pH remained stable for both open tunnel endoscopic vein harvesting and open vein harvesting groups ( P = 0.105 and P = 0.869, respectively). Endothelial integrity was better preserved in the open vein harvesting group compared with open tunnel endoscopic vein harvesting or closed tunnel endoscopic vein harvesting groups ( P = 0.012) and was not affected by changes in carbon dioxide or low pH. Significantly greater stretching of the endothelium was observed in the open tunnel endoscopic open tunnel endoscopic vein harvesting group compared with the other groups ( P = 0.003). Conclusions This study demonstrated that the different vein harvesting techniques impact on endothelial integrity; however, this does not seem to be related to the increase in systemic absorption of carbon dioxide or to the pressurized endoscopic tunnel. The open tunnel endoscopic harvesting technique vein had more endothelial stretching compared with the closed tunnel endoscopic technique; this may be due to manual dissection of the vein. Further research is required to evaluate the long-term clinical outcome of these vein grafts.

Carbon dioxide elimination pattern at cardiopulmonary exercise testing in patients with low ejection fraction value

2020 ◽  
Vol 29 (6) ◽  
pp. 647-653
Author(s):  
O. V. Kamenskaya ◽  
I. Yu. Loginova ◽  
A. M. Chernyavskiy ◽  
D. V. Doronin ◽  
V. V. Lomivorotov
Keyword(s):  
Carbon Dioxide ◽  
Ejection Fraction ◽  
Exercise Testing ◽  
Resting State ◽  
Cardiopulmonary Exercise Testing ◽  
Unfavorable Outcome ◽  
Cardiopulmonary Exercise ◽  
Low Ejection Fraction ◽  
Over Time

The objective of this study was to evaluate partial pressure of end tidal carbon dioxide (PetCO2) over time on exertion (E) and its predictive value in evaluation of risk of unfavorable outcome in patients with low ejection fraction (EF) value.Materials and Methods. Patients (n = 53) with pronounced chronic heart failure (CHF), included in heart transplantation waiting list, were enrolled in the prospective study. All patients underwent cardiopulmonary exercise testing (CPET). Mortality or INCOR left ventricle bypass system implantation according to vital indications within 1 year of follow-up were evaluated as an end-point.Results. Patients with CHF and low EF were characterized by low parameters of E tolerance and peak oxygen consumption (10.4 (9.6–11.7) ml/min/kg). The average PetCO2 level by group was 30.4 (28.3–33.0) mm Hg; in 32% of patients this value decreased or did not change in CPET compared with that in resting state. The significant relationship between increased risk of unfavorable outcome within 1 year of follow-up with low baseline PetCO2 value (odds ratio (OR) – 0.22 (0.05–0.87); p = 0.020) and absence of its increment in PE (OR – 0.16 (0.10–0.54); p = 0.009) was observed.Conclusion. The significant predictive factors of unfavorable outcome within 1 year of follow-up in patients with pronounced CHF and low EF include PetCO2 value in resting state, as well as PetCO2 change over time after E challenge.

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